Gọi tâm mặt cầu là \(I\left(a;0;0\right)\Rightarrow\overrightarrow{AI}=\left(a-1;2;-3\right)\) với \(a>0\)
\(AI^2=R^2\Leftrightarrow\left(a-1\right)^2+2^2+3^2=7^2\)
\(\Leftrightarrow\left(a-1\right)^2=36\Rightarrow\left[{}\begin{matrix}a=7\\a=-5\left(l\right)\end{matrix}\right.\)
Pt mặt cầu: \(\left(x-7\right)^2+y^2+z^2=49\)